1. Field of the Invention
The present invention relates to trimming shears for sheets and strips, and more particularly to trimming shears having two shears frames arranged opposite one another on supports and having a pair of roll blades disposed on diagonally opposite corners of the shears frames.
2. Description of the Related Art
Trimming shears are used to cut sheets and strips of materials having various thicknesses and widths. For example, German Patent No. 41 08 717 C2 discloses trimming shears for cutting a strip or sheet edge with radially and axially staggered interacting roll blades. However, when trimming thin strips or strips of relatively soft material, these trimming shears generate sufficient shear force to: 1) create ripples in the material; 2) cause the edges of the material to bend; and 3) produce other miscellaneous defects. Suitable countermeasures such as, for example, simultaneously driving both of the blades, can reduce such defects. Here, the blades are simultaneously driven by a cogged roll gear mechanism, which is located either in or behind the shears frame and is connected to blade shafts by articulated shafts.
Most trimming shears have two shears frames, each of which carries the roll blades in a float-mounted fashion, i.e. the shears frames can be adjusted on a substantially horizontal plane parallel to the surface of the strip material and at a right angle to the strip cutting direction to set the width of the material being cut. In addition, the roll blades of each roll blade pair can be moved toward and away from one another, in order to allow the pair to be adjusted to different sheet thicknesses. However, the roll blades on trimming shears of this type cannot be changed without taking the machine out of service.
There is accordingly a need for a trimming shears apparatus that is adjustable to a variety of sheet widths and thicknesses and on which the blades may be removed and replaced without having to take the machine out of service.